Surveying Reviewer

 

SURVEYING REVIEWER SURVEYING  - It is the art and science of determining angular and linear measurements to establish the form, extent and relative position of points, lines, and areas on or near the surface of the earth or on other extraterrestrial bodies through applied mathematics and the use of specialized equipment and techniques. CLASSIFICATIONS OF SURVEYING:  

Plane Surveying - Surveys of limited extent,

We consider the earth to be a flat surface.  

Geodetic Surveying - Surveys of wider extent,

Take into account the spheroidal shape of the earth. TYPES OF SURVEYING:  

Cadastral Surveys - Surveys undertaken at rural and urban areas to determine property lines and boundaries.

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objects, Highways, railroads, pipelines, canals, transmission lines and other linear projects.   Topographic surveys - Shape of the ground, Location and elevation of artificial and natural features. Surveying Measurements

- Extent, size or dimensions of a particular quantity in comparison to a given standard - Imperfections of the instruments used - Are never exact and they will always be imperfect no matter how carefully made “No exact or true measurement is ever possible”  possible”   Types of Measurements: Direct Measurements - Comparison of the measured quantity to a standard measuring measuring unit. Indirect Measurements - Not possible to apply a

City  - Surveys of the areas and in and near a citySurveys for expansions, improvements improv ements locating property lines.   Construction Survey - Provide data regarding grades, reference lines, dimensions, dimensions, ground configurations and the location and elevation of structures.   Forestry Surveys - Forest managemen management,t, Production and conservation of forest lands.   Hydrographic Surveys - Surveys of bodies of water, For mapping of shore lines, chart the shape of areas underlying water surfaces,

measuring directly,toObserved valuevalues. is determinedinstrument by its relationship other known

Measure the flow of stream, Important in navigation, development development of water supply, flood control, irrigation and subaqueous constructions. constructions.   Industrial Surveys - Also known as optical tooling, Ship building, and construction and assembly of aircrafts, Lay-out and installation of heavy machinery, Accurate dimensional lay-outs.   Mine Surveys - Positions of underground excavations and surface mine structures, Fix boundaries of mining claims.   Photogrammetric Surveys - Survey using cameras, Satellite images, Google earth, Google

-26.175 to nearest hundredth is 26.18 -156.285 would be 156.28

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maps, drones. Route Surveys - Alignment, grades, earthwork quantities, location of natural and artificial

Rounding off numbers: Digit less than 5

-The number is written without the digit -24.244 to nearest hundredth is 24.24 Digit is equal to 5

-The nearest even number is used

Digit is greater than 5

- The number is written with the preceding digit increased by 1 - 226.276 to nearest hundredth is 226.28 - 226.28 to the nearest tenths is 226.3 Surveying Field Notes:

-Only in the reliable field. and permanent record of actual work done -Official record of the survey. -Clear, complete and systematic.

 

8.  Rear Tape man - assist thd head tapeman 9.  Flagman - hold the flagpole 10.  Rodman-holds the stad 11.  Pacer 12.  Axe man/Lineman man/Lineman - remove obstruction obstruction 13.  Aid man - gamot gamot gamot lang 14.  Utility men - driver,camp out - other form

“There is no phase in a surveyor’s work which is of greater importance, or which requires more careful attention than the keeping of the field notes”  notes”   Types of Notes    

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Sketches - Rarely exact scale, but approximately scaled. Tabulation  - Prevents mistakes, easy checking, saves time, calculations legible to others, simplifies work. Explanatory Notes - Written description of what has been done on the field. Computations - are made algebraically using simple arithmetic and trigonometric functions. Combination of the above - Used in most extensive surveys.

Errors - Difference between the true value and the measured value of a quantity, Inherent in all measurements, measuremen ts, cannot be avoided. Mistakes  - Inaccuracies in measurements, Surveyors carelessness,, inattention, poor judgment and improper carelessness execution.

Information Found in Field Notebooks  

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Title of the Field Work / Name of Project Time of Day and Date Weather Conditions Names of Group Members and Designations List of Equipment Field Survey Party

1.  Chief of Party - responsible for overall directions - logistical and technical requirements - submitting survey reports and records 2.   Assistant Chief of of Party -assist the cop -takes over the duty of cop - conducts ground reconnaissance and investigates site -employment of surveying equipment 3.  Instrument maman- set up, level, operate 4.  Technician - use and operation of all electronic instruments -establishing 2-way communication communication 5.  Computer - perform computation 6.  Recorder - keep the records 7.  Head Tape man - accuracy and speed of all measurements -marking of stations - inspect and compares tape - taping operations

Types of Errors Systematic Errors (Cumulative error)

 

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Errors have same sign constant and magnitude long asthat fieldwill conditions remain constan t and as unchanged.

Accidental Errors

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Purely accidental in character, Either positive or negative, Caused by factors beyond the control of the surveyor. Sources of Errors

Instrumental Errors - Imperfections of the instruments used. Natural Errors - Variations on the phenomena of nature. Personal Errors - Limitations of the senses of sight, touch and hearing of the human observer. Accuracy and Precision: Accuracy  - Closeness between related measurements. Precision - Closeness to one another. Most Probable Value (MPV) - Is the arithmetic mean of a group of repeated measurements. measurements.

FORMULA Mpv = ƩX/n = (x1 + x2 + x3 + . . . +xn)/n

 

Residual or Deviation - The difference between any measured value of a quantity and its most probable value.

FORMULA v = x - mpv

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Moving with measured steps.   Counting the number of steps or paces.   Suitable in situations where low precision is sufficient.    Affected by many factors.

Probable Error - A quantity which when added to or subtracted from the MPV, defines a range within which there is a 50% chance that the true value of the t he

Pace - Length of a step-in walking

measured quantity lies inside (or outside) the limits thus set.

Pace Factor   -- Average length of one’s pace pa ce  FORMULA: PF = TD/ MNP 

FORMULA PES = ± 0.6745 (Ʃv2/n-1)1/2

PEM = ± 0.6745 [Ʃv2/n(n-1)]1/2

Relative Precision - Ratio of the error to the measured quantity. FORMULA RP = PE/mpv

Interrelationship of Errors Summation of Errors 2

2

2

2 1/2

PE   = ± (PE  + PE  +PE  + … +PE )   s

1

2

3

n

Product of Errors 2 1

2

2.  Distance by Taping.   Probably the most common method of measuring or laying out horizontal distances. distances.   Stretching a calibrated tape between two points and reading the distance on the tape. t ape.   Ropes, cords and lines were first used for centuries.   Steel tape came about the beginning of 20th century, now fiber glass tape is used. 3.  Distance by Tachymetry. ( TACHEOMETRY)   Probably the most common method of measuring or laying out horizontal distances. distances.   Stretching a calibrated tape between two points and reading the distance on the tape.   Ropes, cords and lines were first used for centuries.   Steel tape came about the beginning of 20th century, now fiber glass tape is used.

2 1/2.

PE   = ± [(Q  * PE )   + (Q  * PE ) ] p

Stride - Two paces or double steps

2

Stadia Method

1

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Measurement of Distance

One of the basic operations of Plane Surveying is the accurate determination of the distance between two points. This linear measurements means horizontal distances. If the points have different elevation, the distance is the horizontal length between plumb lines. If incline distance is measured, it will be reduced to its equivalent horizontal projection. Methods of Determining Distance 1.  Distance by Pacing.

Rapid means of determining distances   Topographic and reconnaissance survey   Relative Precision of 1/300 to 1/1000 FORMULA: D = Ks + C   Subtense Bar Method  

Convenient and practical device for quick and accurate measurement of distances   Consist of a bar precisely 2m long and a transit or theodolite to measure the subtending angle   Relative Precision is 1/3000

 

= 1 Mathematical / Tan(α Tan(α /2) FORMULA: 4.  Distance by GraphicalDand Methods.

 

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Unknown distances maybe determined through their relationship with known distances geometrically   Maps, Plane Table Surveys, Triangulation, Trilateration 5.  Distance by Mechanical Devices.   Few mechanical devices could also be employed for the measurement of distances   Only for low precision surveys   For quick measurements measurements Distance by Mechanical Devices Odometer    A

simple device that can be attached attached to a wheel   Only gives surface distance   Reduce measured distance to equivalent horizontal distance   Relative Precision is 1/200 Measuring Wheel

Similar to odometer, except it is more portable and self contained.   It has a built in calibrated recorder that automatically gives distance.   Suitable in irregular and curve lines and boundaries.  

Optical Rangefinder  

This device can use to determine distances approximately simply by focusing.   Use in field sketching, reconnaissance, and measurement checking.   Relative Precision is 1/50. 6.  Distance by Photogrammetry.   Measurement of images in a photograph   Relative Precision is 1/3000 to 1/5000 Composition of Taping Party

1.  2.  3.  4. 

Head Tapeman Recorder Flagman Rear Tapeman

The Procedure of Taping

1.   Aligning the Tape Tape 2.  Stretching the Tape 3.  Plumbing

4.  Marking Full Tape Lengths 5.  Tallying Taped Measurements 6.  Measuring Fractional Lengths Breaking Tape - Is the procedure of holding the tape horizontally above ground and to plumb at one or both ends when taping on sloping or uneven terrain surfaces.

SEPTEMBER 01, 2019